Hearing aids are electroacoustic device which amplify sound for the wearer in order to correct hearing deficits as measured by audiometry, usually with the primary purpose of making speech more intelligible. Many hearing aids may be operated in either an omnidirectional or a directional microphone mode, which refers to manner in which the hearing aid's microphone or microphones pick up sound. In an omnidirectional microphone mode, sound is picked up from all directions around the wearer and amplified. In a directional microphone mode, sound is preferentially picked up and amplified from only a single direction, usually in front of the listener. Usually, the omnidirectional microphone mode is used in quiet listening situations because speech often comes from directions other than in front of the listener. The directional microphone mode, on the other hand, may be used in noisy listening situations to enhance the sound coming from someone speaking directly to the hearing aid wearer. Described herein are techniques for automatically switching between omnidirectional and directional microphone modes.